The field of the invention relates to filter assemblies and systems. In particular, the field of the invention relates to filter assemblies for air intake systems. Filter assemblies, including assemblies that utilize annular filter elements, are known in the art. (See, e.g., U.S. Pat. Nos. 7,993,422; 7,981,183; 7,976,601; 7,959,703; 7,931,725; RE42,174; 7,879,125; 7,828,870; RE41,713; 7,799,108; 7,789,926; 7,753,982; 7,740,678; 7,662,216; 7,648,546; 7,625,419; D600,790; 7,563,300; 7,540,895; 7,413,588; 7,323,106; 7,323,105; 7,314,558; 7,282,077; 7,276,098; 7,125,490; 7,097,694; and 6,902,598; the contents of which are incorporated herein by reference in their entireties).
In order to ensure reliable, robust engine operation, engines must be protected from contaminants entering via the air intake system. Filter assembly systems utilize filter elements in this regard to remove contaminants from air intake. In order to improve filter assembly efficiency, it is desirable to incorporate pre-cleaner features into components of the filter assembly. A further issue in filter assemblies is the installation or attempted installation of incorrectly oriented filter elements or unauthorized filter elements that may adversely impact the engine. It is desirable to incorporate features into filter assembly systems in order to reduce or prevent installation of incorrectly oriented filter elements or unauthorized filter elements within filter assembly systems. Accordingly, disclosed herein are pre-cleaner features and installation elements that address these issues.